sites no longer resolving

All of a sudden I've noticed a couple sites that I have set up in ispconfig3 are no longer resolving. My main domain that I used to set up is resolving, but none of the other sites. To be honest, I'm not quite sure where to look for the appropriate logs. I don't see anything referencing mydns in /var/log

The strange thing is, the domains resolve when I check from the VPS, but don't resolve checking from home or anywhere else.

They are, these sites have been running fine for a few months now. All of a sudden I can't resolve them. Stranger yet, I had someone in another location check and they were able to resolve the domains. All of a sudden I'm also blocked out of ssh. My control panel is still running and my other sites are too, I just checked from work and I can see them and resolve them.

The support told me they cleared the hosts.deny, but clearly they did not. I had someone login for me and clear out my IP address. What scares me though is why this happened to begin with. I had both fail2ban and denyhosts installed, should I only use 1 or the other?

I'm still unable to resolve from my home IP address. I can login to the control panel but can't resolve my other sites. They resolved fine from work and I've had a few other people check with no problems.

Is there any other setting that could block access to DNS for this IP?

edit: looks like might have been my router or atts dns. I added another entry and was able to resolve.